package com.gtt.jr.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.lang.StringUtils;

/**
 * SecurityFilter
 * 
 * @author Michael(gao12581@sina.com)
 * @date 2011-3-8 15:31:52
 * 
 */
public class SecurityFilter implements Filter {

	public void destroy() {
	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {

		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse res = (HttpServletResponse) response;
		HttpSession session = req.getSession();
		String username = (String) session.getAttribute("username");
		if (StringUtils.isEmpty(username)) {
			res.sendRedirect(req.getContextPath() + "/login");
		} else {
			chain.doFilter(request, response);
		}
	}

	public void init(FilterConfig filterConfig) throws ServletException {
	}

}
